A question to pchang about plasma propulsion

[DanS]

Originally posted by child of Thor


As Che asks.

By Airship i keep thinking of a Zeplin

Yes. A huge Zeppelin. An airship. A dirigible. The things the NAZIs built. A mile wide and long. This is the easily doable and inexpensive part. Nobody's laughing at this part of the plan, even though it's sure a lot of sewing.

Wouldn't a mile long craft be exceedingly likely to break, regardless?

No. It's doable. The WALRUS, above, is conceived as 1/5 of a mile long and is intended to operate at ground level. This would be to move military equipment worldwide in less than a week.

At great heights, as pchang points out, the air is very thin. The orbital airship is conceived as taking off from about 150,000 feet in altitude rather than from the ground, so could be built merely to survive the atmosphere at those heights.

But escape velocity and or disturbance for such a large craft.......i find it hard to imagine it would make it through the upper atmosphere intact? That exit/entry part always looks like hell for spacecraft.

ITYM, orbital velocity rather than escape velocity. But other than that, you're repeating what I said above. The structure would have to be strong enough to withstand acceleration to orbital velocity in an atmosphere over a week-long period.

[child of Thor]

Is Bush planning on taking over the world with this?

someone should tell him its been tried

I thought with you talking about plasma drives this would be a space based project. But i get it now, its a world conquest with giant balloons thing

wont they be quite vunerable, being so large?

[Odin]

A mile wide blimp, now that would be quite a sight.

[DanS]

Originally posted by child of Thor
Is Bush planning on taking over the world with this?

someone should tell him its been tried

I thought with you talking about plasma drives this would be a space based project. But i get it now, its a world conquest with giant balloons thing

wont they be quite vunerable, being so large?

Two slightly related topics. (1) The Walrus, which is a DARPA program to experiment with worldwide heavy lift and is an example of a very large airship, with possible use of electric propulsion. (2) The orbital airship, which is one man's conception of a way to go to orbit using a quite sizeable high-altitude airship and electric propulsion.

Plasma propulsion is a subset of electric propulsion that requires vacuum or near-vacuum to operate. It tends to allow for higher thrust than other electric propulsion concepts, so I was exploring whether #2 was less crack-pottish under a plasma propulsion scenario.

Besides, Bush will be out of office before completion, so he won't be the one to have the fun with #1.

[pchang]

All geniuses are crackpots but not all crackpots are geniuses

[DanS]

Well, even few balloons have operated at those altitudes, so there's a possibility that he found something through testing that nobody else knows. I'm always hesitant to rubbish novel ideas that were arrived at through testing, because we don't know a lot more than we know for certain.

Sometimes that may mean giving crackpots more coverage than they deserve.

NB: If I were looking at it from an investor's eye, I would be immensely more skeptical.

[realpolitic]

If the balloon doesn't get the ship to a high enough altitude, the remaining 50,000 - 100,000 feet is no big deal. A conventional jet goes to 30,000 feet, flies thousands of miles, and yet it's fuel compartmant is only a few percent of its crafts weight. Even Spaceship one made it to 63 miles, looking more like a jet than a spceship. You only need huge fuel tanks when going into orbit or further. Plama propulsion will bear most of this burden even if no ballons were used.

[DanS]

Not quite sure what your point is. Could you clarify?

[MrFun]

If you see me up there someday, waving back down at you, that's the signal to unleash all the raccoons.